Re: [PATCH v3 07/13] mm/huge_memory: deduplicate zap deposited table call

Suren Baghdasaryan
2026-03-28T19:15:05Z

On Fri, Mar 20, 2026 at 11:07 AM Lorenzo Stoakes (Oracle)
<ljs@kernel.org> wrote:
>
> Rather than having separate logic for each case determining whether to zap
> the deposited table, simply track this via a boolean.
>
> We default this to whether the architecture requires it, and update it as
> required elsewhere.
>
> Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>

Reviewed-by: Suren Baghdasaryan <surenb@google.com>

> ---
> mm/huge_memory.c | 22 ++++++++++------------
> 1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 4add863cd18f..fca44aec6022 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -2337,6 +2337,7 @@ static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd)
> bool zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
> pmd_t *pmd, unsigned long addr)
> {
> + bool has_deposit = arch_needs_pgtable_deposit();
> struct folio *folio = NULL;
> bool flush_needed = false;
> spinlock_t *ptl;
> @@ -2357,23 +2358,19 @@ bool zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
> tlb->fullmm);
> arch_check_zapped_pmd(vma, orig_pmd);
> tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
> - if (vma_is_special_huge(vma)) {
> - if (arch_needs_pgtable_deposit())
> - zap_deposited_table(tlb->mm, pmd);
> + if (vma_is_special_huge(vma))
> goto out;
> - }
> if (is_huge_zero_pmd(orig_pmd)) {
> - if (!vma_is_dax(vma) || arch_needs_pgtable_deposit())
> - zap_deposited_table(tlb->mm, pmd);
> + if (!vma_is_dax(vma))
> + has_deposit = true;
> goto out;
> }
>
> if (pmd_present(orig_pmd)) {
> - struct page *page = pmd_page(orig_pmd);
> + folio = pmd_folio(orig_pmd);
>
> flush_needed = true;
> - folio = page_folio(page);
> - folio_remove_rmap_pmd(folio, page, vma);
> + folio_remove_rmap_pmd(folio, &folio->page, vma);
> WARN_ON_ONCE(folio_mapcount(folio) < 0);
> } else if (pmd_is_valid_softleaf(orig_pmd)) {
> const softleaf_t entry = softleaf_from_pmd(orig_pmd);
> @@ -2388,11 +2385,9 @@ bool zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
> }
>
> if (folio_test_anon(folio)) {
> - zap_deposited_table(tlb->mm, pmd);
> + has_deposit = true;
> add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
> } else {
> - if (arch_needs_pgtable_deposit())
> - zap_deposited_table(tlb->mm, pmd);
> add_mm_counter(tlb->mm, mm_counter_file(folio),
> -HPAGE_PMD_NR);
>
> @@ -2412,6 +2407,9 @@ bool zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
> }
>
> out:
> + if (has_deposit)
> + zap_deposited_table(tlb->mm, pmd);
> +
> spin_unlock(ptl);
> if (flush_needed)
> tlb_remove_page_size(tlb, &folio->page, HPAGE_PMD_SIZE);
> --
> 2.53.0
>